Testing of Growth Curves with Cubic Smoothing Splines

Author(s):  
Tapio Nummi ◽  
Nicholas Mesue
1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.


2019 ◽  
Author(s):  
Meng Mao ◽  
Thomas Carpenter ◽  
Michael Whyte ◽  
Alison Skrinar ◽  
Chao-Yin Chen ◽  
...  
Keyword(s):  

2019 ◽  
Vol 14 (1) ◽  
pp. 28-31 ◽  
Author(s):  
Rowles H. L.

Probiotics are live microorganisms, which when ingested in sufficient amounts, confer health benefits to the host by improving the gut microflora balance. The purpose of this research was to determine whether commercial probiotic products containing multitude of commensal bacteria would reduce the growth rate of pathogenic bacteria, specifically Escherichia coli and Salmonella typhimurium. Growth curves were established, and the growth rates were compared for samples of E. coli, S. typhimurium, Nature’s Bounty Controlled Delivery probiotic, Sundown Naturals Probiotic Balance probiotic, and cocultures of the pathogenic bacteria mixed with the probiotics. The findings of this research were that the commercial probiotics significantly reduced the growth rate of E. coli and S. typhimurium when combined in cocultures. Probiotics containing multiple strains may be taken prophylactically to reduce the risk of bacterial infections caused by E. coli and S. typhimurium. Probiotics could be used to reduce the high global morbidity and mortality rates of diarrheal disease.


2014 ◽  
Vol 9 (2) ◽  
pp. 112-116 ◽  
Author(s):  
Maria Toloudi ◽  
Eleni Ioannou ◽  
Marina Chatziioannou ◽  
Panagiotis Apostolou ◽  
Christos Kiritsis ◽  
...  

Author(s):  
Leah Zilversmit Pao ◽  
Emily W. Harville ◽  
Jeffrey K. Wickliffe ◽  
Arti Shankar ◽  
Pierre Buekens

Metals, stress, and sociodemographics are commonly studied separately for their effects on birth outcomes, yet often jointly contribute to adverse outcomes. This study analyzes two methods for measuring cumulative risk to understand how maternal chemical and nonchemical stressors may contribute to small for gestational age (SGA). SGA was calculated using sex-specific fetal growth curves for infants of pregnant mothers (n = 2562) enrolled in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Study. The exposures (maternal lead, mercury, cadmium, Cohen’s perceived stress, Edinburgh depression scores, race/ethnicity, income, and education) were grouped into three domains: metals, psychosocial stress, and sociodemographics. In Method 1 we created cumulative risk scores using tertiles. Method 2 employed weighted quantile sum (WQS) regression. For each method, logistic models were built with three exposure domains individually and race/ethnicity, adjusting for age, parity, pregnancy weight gain, and marital status. The adjusted effect of overall cumulative risk with three domains, was also modeled using each method. Sociodemographics was the only exposure associated with SGA in unadjusted models ((odds ratio) OR: 1.35, 95% (confidence interval) CI: 1.08, 1.68). The three cumulative variables in adjusted models were not significant individually, but the overall index was associated with SGA (OR: 1.17, 95% CI: 1.02, 1.35). In the WQS model, only the sociodemographics domain was significantly associated with SGA. Sociodemographics tended to be the strongest risk factor for SGA in both risk score and WQS models.


Horticulturae ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 26
Author(s):  
Yaping Ma ◽  
Dapeng Zhang ◽  
Zhuangji Wang ◽  
Lihua Song ◽  
Bing Cao

‘Lingwu Changzao’ (Ziziphus jujuba Mill. cv. Lingwuchangzao), a cultivar of Ziziphus in the Rhamnaceae family, is a traditional jujube cultivar in Ningxia, China. For ‘Lingwu Changzao’, morphological traits are prominent in characterizing fruit yield, quality, and consumer acceptance. However, morphological measurements for ‘Lingwu Changzao’ cultivation are limited. Therefore, the objective of this study is to measure the growing patterns of selected morphological traits during ‘Lingwu Changzao’ fruit development. Eight morphological traits, including four fruit traits (fruit length, diameter, weight, and flesh (mesocarp) thickness), three stone traits (stone length, diameter, and weight), and fruit firmness (also known as fruit hardness), were measured over a 3-mo (months) period, covering a completed fruit development period. Results indicate that the growing patterns of fruit traits coincide with double ‘S’ growth curves, which mainly present the growth of ‘Lingwu Changzao’ fruit. Increases of stone traits terminated in the early fruit growth period, while fruit traits continuously increased till the end of the 3-mo period. That implies a high fruit-stone ratio, i.e., a desirable quality attribute for ‘Lingwu Changzao’ as fresh-eating fruits. The results presented in this study can serve as one part of the standard dataset for jujube fruit cultivation in China, and it can also support decisions in plant breeding and field managements for ‘Lingwu Changzao’.


Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Johannes H. Fischer ◽  
Heiko U. Wittmer ◽  
Graeme A. Taylor ◽  
Igor Debski ◽  
Doug P. Armstrong

Abstract The population of the recently-described Whenua Hou diving petrel Pelecanoides whenuahouensis comprises c. 200 adults that all breed in a single 0.018 km2 colony in a dune system vulnerable to erosion. The species would therefore benefit from the establishment of a second breeding population through a translocation. However, given the small size of the source population, it is essential that translocations are informed by carefully targeted monitoring data. We therefore modelled nest survival at the remaining population in relation to potential drivers (distance to sea and burrow density of conspecifics and a competitor) across three breeding seasons with varying climatic conditions as a result of the southern oscillation cycle. We also documented breeding phenology and burrow attendance, and measured chicks, to generate growth curves. We estimated egg survival at 0.686, chick survival at 0.890, overall nest survival at 0.612, and found no indication that nest survival was affected by distance to sea or burrow density. Whenua Hou diving petrels laid eggs in mid October, eggs hatched in late November, and chicks fledged in mid January at c. 86% of adult weight. Burrow attendance (i.e. feeds) decreased from 0.94 to 0.65 visits per night as chicks approached fledging. Nest survival and breeding biology were largely consistent among years despite variation in climate. Nest survival estimates will facilitate predictions about future population trends and suitability of prospective translocation sites. Knowledge of breeding phenology will inform the timing of collection of live chicks for translocation, and patterns of burrow attendance combined with growth curves will structure hand-rearing protocols. A tuhinga whakarāpopoto (te reo Māori abstract) can be found in the Supplementary material.


Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 365
Author(s):  
Chénangnon Frédéric Tovissodé ◽  
Jonas Têlé Doumatè ◽  
Romain Glèlè Kakaï

The widely used logistic model for epidemic case reporting data may be either restrictive or unrealistic in presence of containment measures when implemented after an epidemic outbreak. For flexibility in epidemic case reporting data modeling, we combined an exponential growth curve for the early epidemic phase with a flexible growth curve to account for the potential change in growth pattern after implementation of containment measures. We also fitted logistic regression models to recoveries and deaths from the confirmed positive cases. In addition, the growth curves were integrated into a SIQR (Susceptible, Infective, Quarantined, Recovered) model framework to provide an overview on the modeled epidemic wave. We focused on the estimation of: (1) the delay between the appearance of the first infectious case in the population and the outbreak (“epidemic latency period”); (2) the duration of the exponential growth phase; (3) the basic and the time-varying reproduction numbers; and (4) the peaks (time and size) in confirmed positive cases, active cases and new infections. The application of this approach to COVID-19 data from West Africa allowed discussion on the effectiveness of some containment measures implemented across the region.


Sign in / Sign up

Export Citation Format

Share Document